The Messengers centers on a mysterious object that crashes down to Earth and a group of seemingly unconnected strangers die from the energy pulse. They then awaken to learn that they have been deemed responsible for preventing the impending apocalypse.

Black-D'Elia will co-star as Erin, the mother of a young girl who is forced to drive an escaped inmate to Houston. She's described as bubbly despite the stress in her life. She's killed by the pulse but wakes up. The casting brings her back into The CW's fold after her recurring role on Gossip Girl. Her credits also include Betrayal and All My Children. She's repped by ICM Partners, Brookside and CESD.

Courtney, meanwhile, will portray Peter, an Emo outsider who is accused of trying to commit suicide when he drowns in a pool from the pulse who gains immense strength when he awakens. Repped by CAA, Principato Young and Felker Toszek, his credits include R.L. Stine's The Haunting Hour and The Between.

O'Donnell will pen the script and serve as a co-EP on the drama from CBS Television Studios and Thunder Road. Basil Iwanyk (The Town) will exec produce, while Kent Kubena and Ava Jamshidi are attached to co-EP.